California can feel good about the fact that it has more than half of all the solar rooftops in America, but now there’s even more to celebrate – the 100,000th such installation and the commitment it signifies.

This milestone demonstrates the substantial opportunity we have to make use of this ample and clean energy source – the sun – and the importance of this effort for all stakeholders to achieve California’s clean energy goals, which are among the most ambitious in the world.

Yesterday, I joined with Steve Malnight, vice president for customer energy solutions at PG&E, in writing an op-ed in the San Jose Mercury News laying out the enormous progress that’s occurring in solar in California and the way we see the future.

The high points:

NRDC and PG&E agree that solar is a key part of California’s energy future.

Government, utilities, researchers, advocates and individuals can work together and avoid divisiveness to exploit this ample and clean energy source.

An infrastructure is needed to support a surge in clean energy innovations.

The electric transmission grid needs to be modernized.

Policies and planning are needed to maximize the value of the grid.

Clear regulations and stable policies at the state level help create an investment climate for a thriving green economy.

The California way

NRDC and PG&E often have different views on energy policy, but progress in the solar arena has brought us together as demand for solar grows.

In some states, thorny issues have pitted utilities against solar power companies and solar customers against non-solar. In California, we’re proud to do things differently. We’re committed to working with all stakeholders to strike a balance that enables us to succeed.

Malnight and I are convinced it’s possible to speed the deployment of solar power, energy efficiency, energy storage, electric vehicles, and other locally generated resources while improving the resiliency of the electric transmission grid and providing opportunities for all to enjoy the benefits of such technologies.

Grist for the grid

There are more than 2,000 new solar rooftops connected to PG&E’s grid every month – a testament to their growing popularity as prices fall. These panels send excess power onto the grid during sunlight hours and draw power from the grid at night.

But it’s not just about panels on rooftops.

Investments in solar power are increasing in many places including California. PG&E now has agreements to buy solar power from seven of the largest projects in the world. By 2020 almost 20 percent of the electricity PG&E’s customers use will come from solar sources. That is enough clean power from the sun to run more than 2 million homes.

Today’s electric grid – which was designed to receive and distribute power in old ways -- needs to be modernized to accommodate solar and wind energy as well as innovative technologies like electric cars and power storage technologies.

The cost structure of the grid is also challenging. Allocating costs fairly among customers is essential to help maintain its financial integrity.

Our electricity grid, deemed “the greatest invention of the 20th century” is now in a new century, facing new demands of its balancing act of physics and governance. Its challenge is to be able to continue to regulate supply and demand instantaneously, providing a shared resource for the benefit of all.

California’s clean energy ambitions

The target for this aggressive campaign is for one-third of the state’s electricity sales to come from renewable sources like solar and wind by the end of this decade. Achieving this goal will require the production of enough clean electricity to power nearly 9 million homes.

Despite the naysayers, success in meeting the RPS is within reach – as long as we continue to support investment in renewable and low-carbon energy resources like PG&E has done with solar.

"...California, we’re proud to do things differently. We’re committed to working with all stakeholders to strike a balance that enables us to succeed."

Part of the California way seems to be loudly tout the highly popular rooftop solar PV, while more cost effective utility scale renewables do the heavy lifting.

This article shows that as of 2012, dispatchable hydro was still the largest renewable source in California, with baseload geothermal (at 2.7 GWatts) the next largest. Wind may have surpassed geothermal by the end of 2012 (in spite of the lower capacity factor), as it currently stands at 5.8 GWatts (according to the AWEA).

The SEIA reports that in the past three years, California has installed 4.2 GWatts of solar PV, 64% of which has been utility scale. In addition to being only half the cost of rooftop, utility scale solar is also safer, and often located in the desert in-land areas, which are substantially sunnier than the California coast (the extra sunniness means not only lower cost, but fewer cloudy days which require fossil fuel backup).

Also at utility scale are the two CSP plants which are expected to come on-line in 2014, the 392 MWatt Ivanpah and 250 MWatt Mojave Solar.

Peter - it appears that you may have made an inadvertent "cut and paste" error. You say -

"California can feel good about the fact that it has more than half of all the solar rooftops in America, but now there’s even more to celebrate – the 100,000th such installation and the commitment it signifies."

This implies that there are only 100,000 solar rooftops installations in CA. However, your editorial seems to make a more reasonable statement -

"One hundred thousand of those are in PG&E's service territory."

In reality California, as a whole, has over 200,000 solar installations, as can be seen from the California state government's Solar Statistics website.

California has made very good progress towards increasing its renewable power ‘net’ generation capacity compared to many other States. To illustrate, solar PV has increased from 1% of total net power generation 12/31/12 up to 3% by 12/31/13. Since total California renewable power ‘net’ generation is currently on the order of 10%, achieving the 20% level by 2020 will be significantly challenging. Increasing distributed roof mounted solar PV will definitely be a significant contribution towards this aggressive RPS goal.

- to look at solar PV in CA you pick the date 12/31 - one of the days with shortest sunlight. Why go back to Dec when you can use yesterday? Closer to 6% for solar yesterday... and it was a short, cloudy day. Better yet, why only pick one day - for the month of March solar was 5% of production on CAISO.

- You say CA renewable power mix is on the order of 10% and that achieving the goal will be significantly challenging. If you look at the CPUC website - you can see that all three major IOUs were near 20% in 2012. PG&E recently announced that renewables were 22.5% of their power mix in 2013.

- the law requires IOUs to have renewables as 33% of their mix by 2020.

- Roof mounted solar cannot be counted against this goal... so increasing distributed roof mounted solar will NOT be a significant contribution. The 200,000 rooftops with 2,000MW of installed panels are not part of the deal.

- Finally, this is not really a challenging goal. There are already significant projects lined up over the next few years. If anything the 33% goal will be hit early. I am guessing that the utilities don't want to hit it too early - since once they do - it will be raised to 50% for 2030.